1. Field of the Invention
This invention relates to a novel grinding device which is capable of easily grinding the cylindrical internal surfaces of a wide variety of machine parts.
2. Description of the Prior Arts
It is ordained by law that the internal faces of the master and wheel cylinders used in the hydraulic brake system in an automobile or other machines should be subjected to re-grinding at the time of a periodical checkup. Heretofore, such re-grinding of the internal faces of the master and wheel cylinders in the hydraulic brake system for an automobile, etc., has been accomplished by the manual work with a sand paper. This method, however, has the defects that it is difficult with such method to uniformly grind the cylindrical internal face and that a long time is required for such grinding work.
As an alternative method for grinding the master and wheel cylinders used in the hydraulic brake system for an automobile, etc., there is known a method in which rotatory force is given by a motor-driven drill or other means to a small-sized honing horn using oil-stone and such oil-stone is pressed against the cylindrical internal face of the work by the centrifugal force. But this method has a disadvantage that it is useless for grinding on a work with a small inner diameter as it is impossible to insert the honing horn composed of plural pieces of oil-stone into the cylinder. Also, in case of using such small-sized honing horn, even if it is possible to insert the honing horn into the cylindrical work to perform desired grinding, it is impossible to replace the oil-stone alone and hence it needs to replace the entire honing horn upon wear of the oil-stone, resulting in elevated working cost. Further, in use of such small-sized honing horn, it is impossible to insert the grinder into the cylinder to be worked if other machine parts or devices are present in the axial direction of the cylinder and hence, in such a case, no grinding work can be performed. Moreover, in case the master and wheel cylinders used in the hydraulic brake system for automobiles, etc., are made of a soft material such as aluminum as often practiced in the industry of late, use of such honing horn proves quite ineffective for grinding on such parts.